Bay's a social hub for whales
A NEW study has provided fresh evidence of the importance of Hervey Bay as a social hub for humpback whales.
The study is part of a long-term research program looking at the social behaviour and organisation of humpback whales, undertaken by Trish and Wally Franklin, the directors of the Oceania Project.
Principal investigator Trish Franklin said the work, to be published in the journal Marine Mammal Science, revealed significant changes in the composition of humpback whale pods during migration.
“It’s not until early September that the main flow of mothers with older calves commences and towards the end of the season, during October and November, mother-calf pods dominate the migration, along with male escorts,” Ms Franklin said.
A surprising finding was mothers with calves in the Bay spend most of their time alone with their calf involved in maternal care.
“When they do socialise, they are more likely to join with other pods which include a mother and calf,” she said.
“This differs greatly from other humpback whale areas, such as Hawaii, where mother-calf pods are usually accompanied by one or more male escorts and rarely are mother-calf pods reported mixing with other mothers and calves.
“In Hervey Bay, only one in 10 mother-calf pods attract one or more male escorts.”
Ms Franklin said over the 14 years of the study from 1992 to 2005 there was a significant increase in larger pods, with three or more humpback whales.
“This is likely to be related to changes in the behaviour of humpback whales as the numbers and density of whales in Hervey Bay increased from approximately 2000 humpback whales in 1992, to around 7000 in 2005,” she said.
Sheltered Hervey Bay, formed by Fraser Island, is conveniently just west of the main migratory pathway and is easily accessible to the whales as they move south from their Great Barrier Reef breeding grounds.
“Geographically this is completely different to areas used by humpback whales in the northern hemisphere, such as Hawaii and the West Indies, where there is only open ocean between the breeding grounds and feeding areas,” Mr Franklin said.
“The combination of the variety of humpback whale social behaviour that occurs as different social groups visit the Bay, and its geography, is why Hervey Bay has become known as a unique whale-watch destination.”
“No matter what time of the season you visit the Bay to see humpback whales, you can expect to observe and experience something different.”
‘No matter what time of the season you visit the Bay to see humpback whales, you can expect to observe and experience something different’